In recent years, environment-related situations have developed serious problems such as an environmental pollution and a global warming. In the automotive sectors, the reduction of emission gas including carbon dioxide is a matter of growing concern.
Further, safety issues are considered to have importance under the current situation of traffic accidents and the like.
One approach to the above problems is that the vehicle is equipped with more intelligent and sophisticated functions intended to improve the current standard of environment-friendly and safer performance of the vehicle. This approach has been implemented after the awareness to those problems and concerns, and has yielded a certain outcome.
The other approach to the above problems is that the drivers are trained to have improved efficiency in terms of driving the vehicle on a lower fuel consumption rate, with improved safety-related driving skills. Therefore, ideas for the improvement of the driving skills of individual drivers have been proposed, which includes, for example, an apparatus for diagnosing driving conditions of the driver while he/she is sitting behind the wheel.
For example, an apparatus disclosed in Japanese patent document JP-A-2000-247162 notifies the driver of diagnosis and evaluation results on multiple diagnosis items based on the detection of the driving conditions and comparison of the detected conditions with standard values.
However, in terms of diagnosis/evaluation accuracy of the driving conditions, some diagnosis items can hardly be diagnosed appropriately in a quantitative manner (i.e., an absolute assessment).
For example, the fuel mileage smaller than a certain standard value in a specific section does not necessarily means that the driving condition in that section is better than the other sections. That is, in other words, the smaller fuel mileage in an expressway, which is usually smaller than the fuel mileage in a local road, should not automatically be diagnosed that the vehicle is in a good driving condition, if, for example, the fuel mileage is not smaller than the average fuel mileage calculated from daily travels of the same expressway section due to over-acceleration or the like. In that case, the driving conditions in the target section may better be diagnosed negatively.